Rock drill



Jufly 9, J. c. CURTIS ROCK DRILL Filed'May 5, 1958 2 Sheets-Sheet 2 Patented July 29, 1941 Q HTED STT$ RQCK DRILL John C. Curtis, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application May 5, 1938, Serial No. 2%,192

8 Claims.

This invention relates to rock drills, and more particularly, but not exclusively, pertains to an improved supporting, guiding and feeding means for a hammer rock drill of the mounted drifter type.

' In hammer rock drills of the mounted drifter type, longitudinal vibrations of substantial intensity are set up within the drill hammer motor during operation of the latter resulting from the force of the jars imparted by the hammer piston, due to the sudden reversals in direction of piston movement, and this vibratory action is employed to effect feed of the drill hammer motor along the drill supporting and guiding means under the control of an automatic ratchet device for automatically checking reverse movement of the hammer motor while permitting the free movement of tl'iehammermotorin the feeding direction. In. such automatic vibration-controlled feeding means, it has been found that the intensity of the vibratory action incident to the operation of the hammer motor, is substantially less at certain times than at others, particularly when the drill hammer motor is operating to drill holes inclined at a substantial angle upwardly or downwardly with respect to the horizontal, due to the weight of the hammer motor opposing the vibratory action of the hammer motor in one direction. It has also been found that during such drilling operations, at substantial inclinations with respect to the horizontal, the vibratory action of the drill hammer motor in the case of a stuck drill steel, was insufficient effectually to accomplish drill steel release, due'to the weight of the hammer motor opposing the vibratory action of the motor in one direction.

Itis an object of the present invention to provide an improved rock drill feeding means operated by a vibratory action set up in the drill hammer motor incident to the operation of the latter, having embodied therein improved means for accentuatingthe vibratory action of the hammer motor whereby an effective automatic feed is obtained at all'times irrespective of the inclination of the drill hammer motor with respect to the horizontal. Another object is to provide an improved supporting and guiding structure for a hammer rock drill. Still another object is to provide an improved supporting and guiding structure for a hammer rock drill wherein a guide shell is employed in the supporting and guiding of the drill hammer motor and which has an improved mounting structure for the guide shell to permit limited reciprocatory movement of the latter whereby the vibratory action set up within the drill hammer motor incident to the operation thereof is accentuated. A still further object of the invention is to provide an improved yieldable sliding mounting structure for the guide shell. Other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanyin drawings there is shown for purposes of illustration one form which the invention may assume in practice.

In these drawings:

Fig. 1 is a side elevati-onal view, with parts shown in longitudinal vertical section, of a hammer rock drill constructed in accordance with an illustrative embodiment of the invention.

Fig. 2 is an enlarged cross sectional view taken substantially on line 22 of Fig. 1.

Fig. 3 is an enlarged horizontal sectional View taken substantially on line 33 of Fig. 1.

Fig. 4 is a View in longitudinal vertical section taken through the feed control means shown in Fig. 1.

Fig. 5 is a cross sectional View taken substantially on line 5-5 of Fig. 4.

Fig. 6 is a view similar to Fig. 5, showing parts in a different position.

Fig. 7 is a cross sectional view taken substantially on line l''f of Fig. 4.

Fig. 8 is a section of the upper part of the mechanism shown in Fig. '7, with parts in a different position.

Fig. 9 is a diagrammatic View showing the improved rock drill in several operative drilling positions with respect to a working face.

In this illustrative embodiment of the invention, there is shown a drill hammer motor, generally designated I, mounted on improved supporting and guiding means, generally designated 2, and having automatic feeding means, generally designated 3, for feeding the hammer motor along the guideways of the supporting and guiding means.

The hammer motor I is of a conventional design and comprises a motor cylinder 4 having front and rear heads 5 and 6 and containing a reciprocatory hammer piston l. The hammer piston has a striking bar 3 for delivering impact blows to the shank of a usual drill steel 9. The drill steel shank is mounted in a conventional manner in a chuck housing Iii suitably secured to the forward end of the motor cylinder. The rear motor head 6 carries a throttle Valve mechanism I l for controlling the supply of motive fluid to the motor cylinder to effect actuation of the hammer piston. As the hammer motor construction and its mode of operation are well known to those skilled in the art, further description thereof is herein considered unnecessary.

The supporting and guiding means 2 comprises an elongated guide shell l5 having longitudinal guideways l6 for slidably receiving lateral guides l1 integral with the cylinder 4 of the hammer motor, thereby providing guideways along which the hammer motor is slidable relative to the guide shell during the feeding operation. The guide shell has, in parallelism with the guideways l6, longitudinal guides l8 slidably mounted in guideways l9 on a bottom trunnion support 20, the latter having a swivel plate 2| adapted for mounting in the clamp of a conventional saddle mounting. The guide shell I5 is yieldably mounted on the bottom trunnion support in a novel manner as will later be explained.

The automatic feeding means 3, which is of the type operated by a vibratory action set up within the drill hammer motor incident to the operation ofthe motor, may assume various forms and herein comprises a control screw 25 extending longitudinally of the guide shell [5 and suitably journaled for rotation thereon. This control screw is threadedly engaged with a control nut 26 fixed in non-rotatable relation within a depending boss 21 formed integral with the hammer motor cylinder 4. While a screw and nut are employed in this instance to control feed, it will be evident that in lieu of a screw and nut, a chain and sprocket or rack and pinion may be used in an equally effective manner. Mounted on the guide shell I5 at the rear end thereof and supported by rods 28 is a control means, generally designated 29, comprising a casing 30 having a chamber 3|. The control means is herein shown for illustrative purposes as of the roller ratchet type, although it will be evident that in lieu of the roller ratchet, various other types of grip devices might be employed, such as a ratchet and pawl mechanism or a frictional grip means. In this construction, the control screw 25 has its rearward end projecting within the casing chamber and has keyed thereto at 32 a sleeve-like member 33; and a collar 34 integral with the control screw and a collar 35 integral with the sleeve-like member provide for a very limited movement of the control screw within the casing 30. The control screw is journaled, through the sleeve-like member 33, at its rear end for rotation in a bearing 36 in a front head member 31 of the casing 30 and in a bearing 33 in a rear head member 39 of the casing 30. A nut 46 and cooperating lock washer hold the sleeve-like member 33 rigidly on the rear end of the control screw. A housing 4| encloses the nut and washer and the collar 35 of the member 33. The casing 3!] has arranged internally therein a rearward, generally cylindrical space 42 and a forward lobed space 43 having a series of enlargements or lobes 44 providing arcuate recesses. The recesses of the lobes are formed on curves which are not arcs of a circle struck with its center in the axis of the control screw, but instead are struck on longer radii. As a result, there are provided in each of the three equally spaced recesses of the lobes 43, adjacent the mid points thereof, points of minimum radial dimension, and the radial dimension of these recesses increases at a small rate towards each end thereof. Within each of these several recesses there are provided a pair of ratchets, herein gripping rolls 45, each of a size too large to be moved to the central point in said space, but of insuflicient diameter to contact simultaneously both with the inner and outer walls of said recess when moved to points near the opposite ends of the latter. Each of these rollers is pressed toward the other and toward the point of minimum radial dimension of said recesses by a spring-pressed plunger 46 having an auctuating spring 41 and arranged in a suitable bore 48. In the relatively cylindrical space 42 there is rotatably supported an annular shifter member 49 provided with three forwardly extending equally-spaced pin or finger portions 50, each of these pin or finger portions extending into a lobe recess and each of insufficient width circumferentially of the spaces to be contacted simultaneously by the gripping rolls 45 at the opposite sides thereof. Accordingly, in one position of the shifter member 49, there is no contact between any finger 50 and any roller 45. The shifter member 49 may be rotated to cause engagement of its several fingers with one or the other series of rollers 45, and for this purpose there is supported for rotation within a radially-opening passage 5| in the casing 30 a member 52 having a pin 53 arranged in eccentric relation to its axis of rotation and adapted to extend into a groove 54 formed in the periphery of the shifter member 49. A handle 55 is provided to rotate the member 52, and a pin 56 fitting in an annular groove 51 in the periphery of the member 52 prevents inadvertent displacement of the latter from its mounting. It will be noted that in effect there is provided a reversible roller clutch or ratchet for the control screw 25, for controlling the direction of rotation of the latter.

The mode of operation of the automatic feeding means may now be explained. It will be noted that in the position of the parts shown in Fig, 5, which corresponds to the position of the handle 55 as shown in Fig. 4, the rollers 45 are all pressed by their plungers 46 into contact with the periphery of the sleeve-like member 33, and therefore, any rotation of the sleevelike member and with it the control screw 25, would be accompanied by a rolling of three gripping rollers into spaces too small to receive them, with the result that the control screw is locked against turning in either direction; and accordingly, if the drill hammer motor I be started, there will result, no matter how violent the, vibrations or jars produced might be, no feed of the hammer motor relative to the shell guideways in either direction. Now, if it is desired to effect feeding movement of the drill hammer motor, the handle 55 may be turned from its central position to a position wherein the parts are in the position shown in Fig. 6. When the drill hammer motor I is operating, any tendencies of the hammer motor, as a result of the vibration or jars incident to its operation, to move in a forward direction will, under these circumstances, result in rotation of the control screw 25 in a feeding direction, while opposite rotation of the control screw is automatically prevented by the ratchet rollers. Any tendencies of the hammer motor to move in the rearward direction will, therefore, be prevented because the control screw 25 can not rotate in a reverse feeding direction, as the ratchet rollers which prevent that direction of rotation will still be fully operative. Thus, the rotation of the control screw 25 within the non-rotatable control nut 26 will cause forward feed of the hammer motor. If it is desired to effect rearward feed. it

is necessary only to move the handle 55 into a position to move the rollers 45 into a position opposite from that shown in Fig. 6, and this will render the rollers which preclude rearward feed inoperative and render the rollers which preclude'forward feed operative again. As this improved automatic feed control means is well known in the art and is not per se my invention, further detailed description thereof is considered unnecessary.

Now referring to the improved yieldable mounting for the guide shell on the bottom trunnion support whereby the vibratory action of the hammer motor in a feeding direction is accentuated, it will be noted that the bottom trunnion support 20 has upstanding end lugs 60 located at the opposite sides of the guide shell, and these lugs have threaded openings GI arranged parallel with the guideways l9 and the shell guideways it. Threadedly secured within the openings iii are adjusting screws E3 having usual lock nuts 6%. As 'shown most clearly in Fig. 3, secured at 65 to the guide shell at the opposite sides thereof and arranged at the rear end of the trunnion support are detachable lateral lugs 56, while formed integral with the guide shell in advance of the trunnion support are lateral lugs 61, and interposed between the lugs 66 and 67 and washers 68 engaging the adjusting screws 63, are coil springs 69. The screws 63 and the lugs 66, 6! have projections 1i) and H respectively entering the coils of the springs 59 to locate properly the latter, the projections H! on the screws also providing positioning and supporting means for the washers 68. Upon adjustment of the screws t3, the tension of the coil springs 69 may be varied. It will be evident that instead of the particular screw, lug and spring arrangement disclosed herein, various other forms of yieldable mountings may be arranged between the guide shell and bottom trunnion support without departing from the spirit of the invention.

The general mode of operation of the improved roek drill is as follows: When the guide shell it is set up in proper position with respect to the working face, as shown diagrammatically in Fig. 9, and the operator manipulates the throttle valve mechanism H, motive fluid is supplied to the motor cylinder 4 of the hammer motor I to effect actuation of the hammer piston l, to actuate percussively the drill steel 9. When the drill hammer motor I is running, the reciprocatory movement of the hammer piston in opposite directions longitudinally of the latter, results in alternating tendencies of movement of the hammer motor forwardly and rearwardly with respect to the guide shell 15. Movement of the hammer motor in a reverse direction along the shell guideways I6 is checked automatically by the control screw 25 and its cooperating control means 29, while free movement of the hammer motor along the shell guideways in the feeding direction is permitted; and as a result the hammer motor by its own vibratory action jumps step by step in a feeding direction automatically along the shell guideways. When the guide shell 95 is in the hori zontal position indicated at A in dotted lines in Fig. 9, it has been found that the vibratory action of the hammer motor was sufiicient to effeet the desired feed of the hammer motor, but when the guide shell was tilted upwardly, as indicated at B in full lines in Fig. 9, the weight of the hammer motor opposed, to a substantial extent, the vibratory action thereof in the forward feeding direction. Also, when the guide shell I5 was supported in a downwardly inclined position, as indicated at C in dotted lines in Fig. 9, the weight of the hammer motor opposed, to a substantial extent, the vibratory action, tending to effect feed of the hammer motor in a reverse feeding direction. To overcome these deficiencies, the improved yieldable mounting structure for the guide shell has been provided. In this improved construction, the longitudinal vibratory action set up within the hammer motor incident to the operation of the latter is transmitted through the control screw 25 and nut 26 to the guide shell l5, causing the latter to reciprocate longitudinally within its guideways l9 relative to the bottom trunnion support 21] against the action of the coil springs 59; and as a result, the vibratory action tending to effect feed of the hammer motor is, to a substantial extent, accentuated. Desirable results may be obtained by adjusting the compression of the springs 69 to produce a frequency of vibration in the drill guideway greater than that of the hammer piston 1. If these springs are highly stressed so that they can provide, as it were, more than half a cycle of movement of the drill guideway during each stroke of the piston 1, it will be appreciated that the cush ioning of the rearward stroke of the piston 1 may result in a compression of the rearward springs 69, and that during the forward movement of the piston l the guideway may be caused, by the expansion of the rearward springs 69, to complete its forward movement and, under the rebound from the forward springs 59, start its rearward movement; and thus an augmented eifect of the checking of the forward movement of the piston 1 may be secured. thereby increasing the forward feed of the drill along the control screw. The vibratory action of the hammer motor provided by the structure described will also increase the effectiveness of the apparatus in releasing stuck steels.

As a result of this invention, it will be noted that an improved rock drill is provided having improved supporting, guiding and feeding means whereby the drill hammer motor is supported, guided and fed in an improved manner. It will further be noted that an improved automatic drill feeding mechanism is provided operated by the vibratory action set up within the drill harnmer motor incident to the operation of the latter whereby the hammer motor is fed relative to the supporting and guiding means in an improved manner. It will also be noted that by the provision of the improved yieldable mounting structure for the guide shell, the vibratory action of the hammer motor tending to effect feed is greatly accentuated, so that an eifeotive feeding force is attained irrespective of the inclined operating position of the hammer motor with respect to the horizontal. Other uses and advantages of the improved rock drill will be clearly apparent to those skilled in the art.

While there is in this application specifically described one form which the invention may as sume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I olaim as new and desire to secure by Letters Patent is:

1; A rock drill comprising, in combination, a drill steel actuating motor of the hammer type in which longitudinal vibrations in opposite directions occur during running of the motor, a guide having a longitudinal guideway along which said hammer motor is movable, means operated by said vibratory action of said hammer motor for feeding the latter along said guide, and a yieldable mounting for said guide, yieldable in the direction of said vibratory movement of said hammer motor, to permit limited longitudinal reciprocatory movement of said guideway for accentuating said vibratory action.

2. A rock drill comprising, in combination, a drill steel actuating motor of the hammer type in which longitudinal vibrations in opposite directions occur during running of the motor, a guide having a longitudinal guideway along which. said hammer motor is movable, means operated by said vibratory action of said hammer motor for feeding the latter along said guide, and a yieldable mounting for said guide, yieldable in the direction of said vibratory movement of said hammer motor, to permit limited longitudinal reciprocatory movement of said guide for accentuating said vibratory action, said yieldable mounting comprising a support having a longitudinal guideway parallel to the guideway of said guide and means comprising resilient elements for connecting said guide to said support for limited reciprocatory movement relative to the latter.

3. A rock drill comprising, in combination, a drill steel actuating motor of the hammer type in which longitudinal vibrations in opposite directions occur during running of the motor, a guide having a longitudinal guideway along which said hammer motor is movable, means operated by said vibratory action of said hammer motor for feeding the latter along said guide, and a yieldable mounting for said guide yieldable in the direction of said vibratory movement of said hammer motor to permit limited longitudinal reciprocatory movement of said guide for accentuating said vibratory action, said yieldable mounting comprising means for guiding said guide for lengthwise reciprocatory movement and resilient means, acting to maintain said guide in a position for movement in either direction from an intermediate position, for connecting said guide to the guiding means therefor for limited reciprocation.

4. A rock drill comprising, in combination, a drill steel actuating motor of the hammer type in which longitudinal vibrations in opposite directions occur during running of the motor, a guide having a longitudinal guideway along which said hammer motor is movable, means operated by the vibratory action of said hammer motor for feeding the latter along said guide, and a yieldable mounting for said guide, yieldable in the direction of said vibratory movement of said hammer motor, to permit limited longitudinal reciprocatory movement of said guide for accentuating said vibratory action, said yieldable mounting comprising a support having a longitudinal guideway parallel to the guideway of said guide and means comprising oppositely acting coil springs for connecting said guide to said support for limited reciprocatory movement relative to the latter.

5.'A rock drill comprising, in combination, a drill steel actuating motor of the hammer type in which longitudinal vibrations in opposite directions occur during running of the motor, a guide having a longitudinal guideway along which said hammer motor is movable, means operated by the vibratory action of said hammer motor for feeding the latter along said guide, and a yieldable mounting for said guide, yieldable in the direction of said vibratory movement of said hammer motor, to permit limited longitudinal reciprocatory movement of said guide for accentuating said vibratory action, said yieldable mounting comprising a support having a longitudinal guideway parallel to the guideway of said guide, said support having lateral lugs, lugs on said guide and oppositely acting coil springs interposed between said lugs for connecting said guide to said support for limited reciprocatory movement relative to the latter.

6. A rock drill comprising, in combination, a drill steel actuating motor of the hammer type in which longitudinal vibratory movements in opposite directions occur during running of the motor, a guide having a longitudinal guideway along which said motor is movable during feeding, means operated by said vibratory movements of said motor for automatically feeding said motor along the guideway of said guide, and means for yieldingly mounting said guide for longitudinal movements in opposite directions along a path in parallelism with the path of said vibratory movements of said motor for accentuating said vibratory action.

7. A rock drill comprising, in combination, a drill steel actuating motor of the hammer type in which longitudinal vibratory movements in opposite directions occur during running of the motor, a guide having a longitudinal guideway along which said motor is movable during feeding, means operated by said vibratory movements of said motor for automatically feeding said motor along the guideway of said guide, and means for yieldingly mounting said guide for longitudinal movements in opposite directions along a path in parallelism with the path of said vibratory movements of said motor for accentuating said vibratory action, said yieldable mounting means including a support having a guideway parallel to the guideway of said guide, said guide slidably mounted in said support guideway, and oppositely acting resilient means connected between said support and said guide.

8. In combination, in a drilling apparatus, a drill steel actuating motor of the hammer piston type, a longitudinal guideway along which said motor is movable during feeding in a direction longitudinally of said motor, means operatively connecting said motor to said guideway and actuated by the jars imparted to said motor by the hammer piston of the latter for effecting feeding of said motor along said guideway, and means for accentuating the vibratory action resulting from said jars to promote feeding including means for supporting said guideway for opposite longitudinal movements along a path at least substantially parallel to the path of the motor along said guideway and means for resiliently opposing movements of said guideway in either direction from an intermediate position.

J. C. CURTIS.

CERTIFICATE OF- CORRECTION. Patent No. 2,251,225 July 29, 19L 1.

JOHN c. CURTIS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 7, for "auctuating" read "actuatingpage 1;, first column, line 12, claim 1, for "guideway"- read guideand that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 50th day of September, A. D. 1911.1.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

